1. Field of the Invention
The invention relates to apparatus and methods for galvanic or electrolytic treatment of printing cylinders.
2. Information Disclosure Statement
An apparatus for electrolytical treatment of printing cylinders has become known under the trademark "Cr-jet-Master" of the assignee of the entire interest, and is shown in FIG. 1. In that apparatus, the current supply takes place via carbon brushes located between the two bearings of the tail spindle in immediate electrical contact therewith. In consequence, the tail spindle, mechanically loaded by the printing cylinder being treated, in the region of its bearings and also by the bearings themselves, is heated by electric current conduction and friction of the carbon brushes, if the electric current is not adequately limited. Enlargement of the cross-section used for current conduction is impossible in view of the dimensions of the electrolyte trough, if in case of printing cylinders of various diameters an optimum spacing of about forty millimeters with respect to the anodes provided at the slanted walls of the electrolyte trough is to be preserved also during treatment of the smaller printing cylinders.
Reference may in this respect also be had to Swiss Patent Nos. 637997 and 639431, by Max Brenner et al, issued Aug. 31, 1983 and Nov. 15, 1983, respectively, to Graphicart Internationale Ausrustungsgesellschaft fur graphische Kunst AG, for apparatus for copper-plating rotary structures, especially rotogravure printing cylinders, wherein current conduction proceeds from the rotary structure through wedge-shaped abutting ring segments and a non-rotary conductor extending through a rotary bellows. European Patent Publication No. 0 082 268, by Karl Saueressig, of Saueressig & Co., published June 29, 1983, for apparatus for electroplating a rotary printing cylinder, discloses an arrangement in which carbon brushes contact a sleeve at a side of a bearing opposite the side at which that sleeve contacts the printing cylinder.